TUESDAY, April 15, 2014 (HealthDay News) -- Children born to
mothers who gain either too much or too little weight during
their pregnancy are more likely to be overweight or obese, a
new study has found.

Putting on too few or too many pounds during a pregnancy
"may permanently affect mechanisms that manage energy balance
and metabolism in the offspring, such as appetite control and
energy expenditure," study author Sneha Sridhar, of Kaiser
Permanente's Division of Research, theorized in a Kaiser news
release.

"This could potentially have long-term effects on the
child's subsequent growth and weight," she said.

In the study, Sridhar's team looked at the medical records
of children aged 2 to 5 born to more than 4,100 women in
California.

They found that 20.4 percent of those children whose mothers
gained more than the recommended amount of weight during
pregnancy were overweight or obese, compared to 14.5 percent of
those whose mothers gained weight within recommended
guidelines.

Similar numbers arose when the researchers compared
overweight rates for children whose mothers gained less
than the recommended amount of weight during pregnancy.

Among women with a body-mass index (a measurement of body
fat based on height and weight) in the normal range before
pregnancy, those who gained less than the recommended amount of
weight during pregnancy were 63 percent more likely to have an
overweight or obese child, the researchers said. The risk was
80 percent higher among those who gained more than recommended
amount of weight during their pregnancy.

The study could only point to an association between
pregnancy weight gain and a child's risk for obesity; it could
not prove cause and effect. But according to senior study
author Monique Hedderson, also from Kaiser Permanente, the fact
that the trend was found among non-obese, normal weight women
"suggests that perhaps weight gain in pregnancy may have an
impact on the child that is independent of genetic
factors."

Current Institute of Medicine guidelines for weight gain
during pregnancy are: for obese women (a BMI of 30 or above),
11 to 20 pounds; for overweight women (BMI of 25 to 29), 15 to
25 pounds; for normal weight women (BMI Of 18.5 to 25), 25 to
35 pounds; and for underweight women (BMI under 18.5), 28 to 40
pounds.

The study was published April 14 in the American Journal
of Obstetrics and Gynecology.